1211012211221 has 2 divisors, whose sum is σ = 1211012211222. Its totient is φ = 1211012211220.

The previous prime is 1211012211163. The next prime is 1211012211287. The reversal of 1211012211221 is 1221122101121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1155379912996 + 55632298225 = 1074886^2 + 235865^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211012211221 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211012211221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211072211221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605506105610 + 605506105611.

It is an arithmetic number, because the mean of its divisors is an integer number (605506105611).

Almost surely, 2^{1211012211221} is an apocalyptic number.

It is an amenable number.

1211012211221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211012211221 is an equidigital number, since it uses as much as digits as its factorization.

1211012211221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1211012211221 its reverse (1221122101121), we get a palindrome (2432134312342).

The spelling of 1211012211221 in words is "one trillion, two hundred eleven billion, twelve million, two hundred eleven thousand, two hundred twenty-one".